"Gun control" is a political and social issue that people debate about often in the United States.
U.S. citizens have had the freedom to own guns since the country began. However, since the 1960s, some people have started to believe that this is dangerous. They believe that citizens should not be allowed to own guns, or that the government should have stricter laws on who can get guns, or what kinds of guns people can own.
Other people feel very strongly that the right to own guns should not be taken away.
This issue or debate is called "gun control". If you are "in favor of" gun control, it means that you think that guns should be controlled more by the government. If you're against gun control, it means that you think that citizens should remain free to own guns.